Segmental Renal Artery Clamping Research Articles

A novel 3D deep learning model to automatically demonstrate renal artery segmentation and its validation in nephron-sparing surgery.

PurposeNephron-sparing surgery (NSS) is a mainstream treatment for localized renal tumors. Segmental renal artery clamping (SRAC) is commonly used in NSS. Automatic and precise segmentations of renal artery trees are required to improve the workflow of SRAC in NSS. In this study, we developed a tridimensional kidney perfusion (TKP) model based on deep learning technique to automatically demonstrate renal artery segmentation, and verified the precision and feasibility during laparoscopic partial nephrectomy (PN).MethodsThe TKP model was established based on convolutional neural network (CNN), and the precision was validated in porcine models. From April 2018 to January 2020, TKP model was applied in laparoscopic PN in 131 patients with T1a tumors. Demographics, perioperative variables, and data from the TKP models were assessed. Indocyanine green (ICG) with near-infrared fluorescence (NIRF) imaging was applied after clamping and dice coefficient was used to evaluate the precision of the model.ResultsThe precision of the TKP model was validated in porcine models with the mean dice coefficient of 0.82. Laparoscopic PN was successfully performed in all cases with segmental renal artery clamping (SRAC) under TKP model’s guidance. The mean operation time was 100.8 min; the median estimated blood loss was 110 ml. The ischemic regions recorded in NIRF imaging were highly consistent with the perfusion regions in the TKP models (mean dice coefficient = 0.81). Multivariate analysis revealed that the feeding lobar artery number was strongly correlated with tumor size and contact surface area; the supplying segmental arteries number correlated with tumor size.ConclusionsUsing the CNN technique, the TKP model is developed to automatically present the renal artery trees and precisely delineate the perfusion regions of different segmental arteries. The guidance of the TKP model is feasible and effective in nephron-sparing surgery.

Renal Functional and Perioperative Outcomes of Retroperitoneal Robot-Assisted Versus Laparoscopic Partial Nephrectomy with Segmental Renal Artery Clamping.

Background: Retroperitoneal approach and segmental renal artery clamping in partial nephrectomy are techniques that facilitate postoperative recovery and renal function preservation. This study aimed to compare the renal function preservation and perioperative outcomes of robot-assisted partial nephrectomy (RAPN) and laparoscopic partial nephrectomy (LPN) with these techniques. Materials and Methods: Clinical parameters of 43 patients who had undergone retroperitoneal RAPN from March 2017 to December 2019 were retrospectively collected and compared with those of 52 patients who had undergone retroperitoneal LPN at the same period in our institution. Differences in operating time, warm ischemia time, estimated blood loss, complications, postoperative hospital stay, as well as renal function loss were compared between the two groups. Results: Background characteristics between RAPN and LPN groups such as age, gender, BMI, and tumor characteristics were comparable. All RAPNs and LPNs were successfully completed without conversion to open surgery or nephrectomy. No significant difference in operating time, estimated blood loss, complications, and postoperative hospital stay was observed between RAPN and LPN groups. The warm ischemia time in RAPN group was slightly shorter than that of LPN groups (P = .054). Compared with the LPN group, the RAPN group was significantly associated with less glomerular filtration rate reduction and renal volume loss rate (P = .042 and P = .013, respectively). Conclusions: The perioperative outcomes were comparable between the two groups. However, compared with LPN, RAPN had superiority in preserving renal function in our series.

Video 10 - Selective Segmental Renal Artery Clamping During Retro and Trans-Peritoneal Robotic-Assisted Laparoscopic Partial Nephrectomy for Hilar Tumours: Technique and Outcome

Video 10 - Selective Segmental Renal Artery Clamping During Retro and Trans-Peritoneal Robotic-Assisted Laparoscopic Partial Nephrectomy for Hilar Tumours: Technique and Outcome

AB021. Selective segmental renal artery clamping during retro and trans-peritoneal robotic-assisted laparoscopic partial nephrectomy for hilar tumours: technique and outcome

AB021. Selective segmental renal artery clamping during retro and trans-peritoneal robotic-assisted laparoscopic partial nephrectomy for hilar tumours: technique and outcome

Comparative study on the curative effect of laparoscopic nephron sparing surgery and renal functions under selective segmental renal artery clamping and main renal artery clamping.

Objective:To discuss the clinical effect and safety evaluation of laparoscopic nephron sparing surgery (LNSS) under selective segmental renal artery clamping (SSRAC) and main renal artery clamping (MRAC).Methods:Eighty-four patients with T1 localized renal tumors who were admitted and treated from October 2017 to October 2018 were retrospectively analyzed, and they were classified into the S group (42 patients) and M group (42 patients). The patients in the S group received LNSS under SSRAC, while the patients in the M group received LNSS under MRAC. The duration of the operation, amount of intraoperative blood loss, intraoperative warm ischemia time, duration of postoperative hospital stay and positive rate of incisal edge; the serum creatinine and blood urea nitrogen values before and after the operation; and the occurrence rates of intraoperative and postoperative complications were compared.Results:All operations were completed smoothly. No patients had a positive incisal edge, and no patients were converted to MRAC during the operation. The duration of the operation and the amount of intraoperative blood loss increased in the S group compared with the M group. The differences were statistically significant (P <0.05). The differences in the intraoperative warm ischemia time, postoperative drainage and duration of postoperative hospital stay in both groups had no statistical significance (P >0.05). The differences in serum creatinine (SCr) and blood urea nitrogen (BUN) in both groups before the operation had no statistical significance (P >0.05). The SCr and BUN levels significantly increased 1 d and 1 m after the operation. The SCr and BUN levels 1 d and 1 m after the operation were significantly lower in the S group than in the M group, and the differences were statistically significant (P <0.05). The differences in the occurrence rates of intraoperative and postoperative complications in both groups had no statistical significance (P >0.05).Conclusion:SSRAC is a new renal artery clamping technology, and its curative effect on LNSS patients is significant. In addition, SSRAC has high safety and little influence on renal functions.

Robot-assisted Partial Nephrectomy with Segmental Renal Artery Clamping: A Single Center Experience.

The aim of our study is to evaluate the feasibility and effectiveness of robotic partial nephrectomy per-formed with segmental clamping of tumor-feeding arteries. Thirty-six patients with renal tumor who underwent robotic partial nephrectomy with segmental renal artery clamping were included in this study. Prospectively recorded patient demographics, mean operation time, estimated blood loss, warm ischemia time, length of hospital stay, pre- and postoperative renal functions and oncological outcomes were analyzed retrospectively. All complications were graded based on the modified Clavien-Dindo classification system. Surgical success was defined as no conversion from segmental artery clamping to the main renal artery clamping. Mean tumor size was 40 mm and, R.E.N.A.L nephrometry score was 6.74. Mean operation time, esti-mated blood loss and warm ischemia time were 162 min, 236 ml, and 16 min, respectively. Five postoperative complications were observed. There were no significant differences in terms of renal functional outcomes before and after surgery (P = .18). Of 36 patients, 34 were completed successfully; however, main renal artery clamping was required in two patients due to excessive bleeding from the tumor bed. The success rate of the segmental renal artery clamping technique was determined as % 94.4 (34/36) in our study. Segmental renal artery clamping may be considered as a reliable and effective surgical method for vascular control during robotic partial nephrectomy. For this technique, tumor characteristics and intrarenal vascu-lar anatomy should be precisely evaluated by the preoperative contrast-enhanced computerized tomography with 3-D reconstruction.

Evaluation of surgery-related kidney volume loss to predict the outcomes of laparoscopic partial nephrectomy with segmental renal artery clamping.

Laparoscopic partial nephrectomy (LPN) with segmental renal artery clamping has become an important method to minimize the warm ischemia of the kidney during the surgery. In the present study, we adopted a new model of calculating surgery-related kidney volume loss (SKVL), which was derived from the imaging technology to predict the outcomes of LPN with segmental renal artery clamping. A total of 111 consecutive patients underwent LPN with available pre- and post-operation computed tomography (CT) scanning data were retrospectively analyzed. The SKVL was calculated using the parameter derived from the CT scan. The correlation between the SKVL and the perioperative outcomes as well as the renal function loss was estimated by the logistic regression analyses. The mean SKVL was 8.99cm3; kidney volume and tumor volume was 147.48cm3 and 25.87cm3, respectively. The SKVL was associated with maximum diameter of tumor (P = 0.001), tumor volume (P < 0.001), intraoperative blood loss (P < 0.001), and the warm ischemia time (P = 0.004), but not associated with the surgery time (P = 0.322) and complications (P = 0.638). Besides, the SKVL was associated with the renal function loss after LPN (P < 0.001). The multivariable logistic regression showed that SKVL was an independent parameter to predict the renal function loss. SKVL is a pre-operation parameter derived from the imaging data, which may be used to predict the perioperative outcomes and renal function loss of patients undergoing LPN.

The margin strategy in laparoscopic partial nephrectomy with selective renal artery clamping: Anatomical basis, surgical technique and comparative outcomes

To evaluate the possibility and efficiency of a modified margin strategy in laparoscopic partial nephrectomy with selective renal artery clamping. Seventy-six cases of laparoscopic partial nephrectomy with segmental renal artery clamping in Shanghai Changhai Hospital between July 2014 and September 2017 were retrospectively reviewed. Relevant clinical data were recorded including baseline patient and tumor characteristics, and surgical outcomes (segmental artery mobilization time, operating time, warm ischemic time, estimated blood loss, complications, and so on). A comparative analysis between standard technique and margin strategy was performed. In 38 cases, margin strategy to mobilize segmental artery was successfully performed. In the other 38 cases, the surgery was performed in traditional method. The use of new strategy led to a shortened segmental artery mobilization time (5min vs 12min, p<0.001). There was no difference in terms of perioperative complications between the two techniques. The margin strategy is a practical method in laparoscopic partial nephrectomy with selective renal artery clamping. It provides a simplified way of finding segmental arteries. Further studies are needed to confirm these preliminary findings.

Long-term renal function following zero ischemia partial nephrectomy.

Partial nephrectomy (PN), also known as nephron sparing surgery, is considered as the first-line treatment in small renal masses, especially in T1/2 tumors, and is applied as a standard treatment in advanced centers. The main expected outcomes from an ideal PN are surgical margin negativity, minimal impairment in renal function, and any surgical complications. Many authors have defined PN techniques as “zero ischemia partial nephrectomy”, where surgery is performed without clamping the main renal artery in order to protect the renal parenchyma from ischemic injury. Various PN techniques employed by surgeons include: selective or segmental renal artery clamping technique; off-clamp, clampless, or unclamped technique; preoperative superselective transarterial tumor embolization technique; sequential/modified sequential preplaced suture renorrhaphy technique, radio frequency ablation-assisted technique, and combination of these techniques. The common goal of all these techniques is to provide zero ischemia without hilar clamping. This systematic review focuses on the long-term functional outcomes of PNs performed by zero ischemia techniques.

Application of a Functional3-dimensional Perfusion Model in Laparoscopic Partial Nephrectomy With Precise Segmental Renal Artery Clamping

ObjectivesTo assess the feasibility of a novel functional perfusion model based on enhanced computed tomography (CT) for the evaluation of split renal function and orientation of segmental renal artery clamping during laparoscopic partial nephrectomy (LPN). Materials and MethodsFrom December 2016 to November 2017, functional perfusion model was applied in 91 patients with T1a renal tumors who had undergone LPN with segmental renal artery clamping. Split computed tomographic-glomerular filtration rate (CT-GFR) was calculated using the 2-point Patlak plot technique. Parenchymal perfusion areas of segmental renal arteries were marked, and target segmental arteries were determined by the perfusion areas wherein tumors were confined. LPN with precise segmental renal artery clamping was performed based on the novel model. Correlations between CT-GFR and estimated GFR and radioisotope GFR were analyzed using Pearson's method. Intraoperative ischemic status and surgical outcomes were assessed. ResultsMean tumor size was 2.9cm. Large tumors were accompanied by more feeding lobar arteries than segmental arteries. CT-GFR was strongly correlated with estimated GFR (r = 0.70) and radioisotope GFR (r = 0.88). All LPNs were successful without converting to main renal artery clamping. Mean operation time was 81.8 minutes; median estimated blood loss was 120mL. The actual parenchymal ischemic region observed during the operation was consistent with the prediction of the perfusion model in all patients. No arterial bleeding or other uncontrollable defect bleeding occurred during tumor resection. ConclusionThis model is a reliable method for the determination of split renal function and orientation of segmental artery clamping during LPN.

The C.L.A.M.P. Nephrometry score: A system for preoperative assessment of laparoscopic partial nephrectomy with Segmental Renal Artery Clamping

Laparoscopic partial nephrectomy with segmental renal artery clamping is associated with a less warm ischemic injury and better postoperative affected renal function compared with main renal artery clamping. However, its indication remains unclear. We established a standardized nephrometry scoring system (The C.L.A.M.P. Nephrometry Score) to evaluate its flexibility in preoperative assessment. This scoring system based on 5 components. The ranking (C)oefficient of each score and the (L)ocation of the clamping position of the target artery and areas of the target artery entering the renal sinus: (A)nterior boundary, (M)ulti-boundary and (P)osterior boundary. We applied this system to analyze data from 106 consecutive patients who underwent SRAC during LPN and divided these patients into 3 groups based on their C.L.A.M.P. scores. The rate of conversion to main renal artery clamping and clamping success rate and the affected side GFR reduction showed significant differences among the groups (P < 0.001). However, parameters such as blood loss, Warm ischemia time and postoperative hospitalization were not significantly different. The C.L.A.M.P. nephrometry score shows strong ability in distinguishing different complexities of artery characteristics and plays a promising role in identifying patients who are suitable for the SRAC technique.

Application and analysis of retroperitoneal laparoscopic partial nephrectomy with sequential segmental renal artery clamping for patients with multiple renal tumor: initial experience

BackgroundTo explore the feasibility and safety of retroperitoneal laparoscopic partial nephrectomy with sequential segmental renal artery clamping for the patients with multiple renal tumor of who have solitary kidney or contralateral kidney insufficiency.MethodsNine patients who have undergone retroperitoneal laparoscopic partial nephrectomy with sequential segmental renal artery clamping between October 2010 and January 2017 were retrospectively analyzed. Clinical materials and parameters during and after the operation were summarized.ResultsNineteen tumors were resected in nine patients and the operations were all successful. The operation time ranged from 100 to 180 min (125 min); clamping time of segmental renal artery was 10 ~ 30 min (23 min); the amount of blood loss during the operation was 120 ~ 330 ml (190 ml); hospital stay after the operation is 3 ~ 6d (5d). There was no complication during the perioperative period, and the pathology diagnosis after the surgery showed that there were 13 renal clear cell carcinomas, two papillary carcinoma and four perivascular epithelioid cell tumors with negative margins from the 19 tumors. All patients were followed up for 3 ~ 60 months, and no local recurrence or metastasis was detected. At 3-month post-operation follow-up, the mean serum creatinine was 148.6 ± 28.1 μmol/L (p = 0.107), an increase of 3.0 μmol/L from preoperative baseline.ConclusionsFor the patients with multiple renal tumors and solitary kidney or contralateral kidney insufficiency, retroperitoneal laparoscopic partial nephrectomy with sequential segmental renal artery clamping was feasible and safe, which minimized the warm ischemia injury to the kidney and preserved the renal function effectively.

Retroperitoneal laparoscopic partial nephrectomy with segmental renal artery clamping for cancer of the left upper calyx: a case report

BackgroundCurrently, the standard treatment for renal pelvis carcinoma is radical nephroureterectomy with bladder cuff excision. To describe the feasibility of retroperitoneal laparoscopic partial nephrectomy with segmental renal artery clamping for cancer of renal pelvis, we report this special case for the first time.Case presentationA 67-year-old woman received this operation. Preoperative ureteroscopy revealed a papillary neoplasm with a pedicle in the upper calyx of the left kidney. After entering the retroperitoneal space and dissociating the renal artery and renal vein, the target artery was clamped beyond the final bifurcation before entering the parenchyma. After incision of the left renal parenchyma and exposure of the upper calyceal neck, the tumor was found confined to the upper calyx. Thereafter, the renal calyx and parenchyma were sutured successively after complete resection of the neoplasm. Postoperative pathological examination confirmed that the Grade I papillary carcinoma was confined to the mucosal layer. Thus far, there is no evidence of recurrence during the follow-up period for more than 42 months after surgery.ConclusionsRetroperitoneal laparoscopic partial nephrectomy with segmental renal artery clamping of the kidney provides a feasible treatment modality for noninvasive tumors that are limited to the calyx.

Laparoscopic Partial Nephrectomy With Sequential Precise Tumor-specific Segmental Renal Artery Clamping for Multiple Ipsilateral Renal Tumors: A New Treatment Approach and Initial Experience

To present our surgical approach and initial experience of laparoscopic partial nephrectomy (LPN) with sequential precise tumor-specific segmental renal artery clamping in patients with multiple ipsilateral renal tumors. Six patients with multiple ipsilateral renal tumors having imperative indications for nephron-sparing surgery underwent LPN with sequential precise tumor-specific segmental renal artery clamping from May 2012 to September 2015. Patient demographics, perioperative variables, renal functions, and postoperative outcomes were reviewed. Overall 15 tumors in 6 patients underwent the sequential precise tumor-specific segmental renal artery clamping LPN without conversion to conventional main renal artery clamping, open surgery, or radical nephrectomy. No severe complication occurred. Mean size of the tumors was 2.5 cm (range 1.8-3.5). Mean tumor-related warm ischemia time was 17 min (range 13-22). The affected kidney functions minimally decreased at recent follow-up and restored 3 months later. No positive tumor margin or extrarenal invasion breakthrough renal capsule was observed after pathologic analysis. Over 12 months' follow-up, no local recurrence and distant metastasis were discovered in these cases postoperatively. LPN with sequential precise tumor-specific segmental renal artery clamping is a feasible approach for multiple ipsilateral renal tumors. It minimizes intraoperative warm ischemic injury and promotes encouraging postoperative function of the affected kidney.

Application of retroperitoneal laparoscopic partial nephrectomy with sequential segmental renal artery clamping for patients with multiple renal tumors

Objective To explore the feasibility and safety of retroperitoneal laparoscopic partial nephrectomy with sequential segmental renal artery clamping for the patients with multiple renal tumors and solitary kidney or contralateral kidney insufficiency. Methods Seven patients who have undergone retroperitoneal laparoscopic partial nephrectomy with sequential segmental renal artery clamping between October 2010 and October 2016 were retrospectively analyzed, and clinical materials and parameters during and after the operation were summarized, including operation time, clamping time of segmental renal artery, blood loss during the operation, complications and renal function after the operation. Results Fifteen tumors were resected in 7 patients and the operations were all successful. The operation time ranged from 100 to 180 minutes with the average of 125 minutes; clamping time of segmental renal artery was 10-30 minutes with the average of 23 minutes; the amount of blood loss during the operation was 120-330 ml with the average of 190 ml; hospital stay after the operation is 3-6 d with the average of 5 d. There was no complication during the perioperative period, and the pathology diagnosis after the surgery showed that there were 4 renal clear cell carcinomas, 1 papillary carcinoma and 2 perivascular epithelioid cell tumors and the margins were all negative. All patients were followed up for 3-60 months, and no local recurrence or metastasis was detected, and the creatinine was 102-187 μmol/L at 3 months after operation. Conclusions For the patients with multiple renal tumors and solitary kidney or contralateral kidney insufficiency, retroperitoneal laparoscopic partial nephrectomy with sequential segmental renal artery clamping was feasible and safe, which minimized the hot ischemia injury to the kidney and preserved the renal function effectively. Key words: Kidney neoplasms; Retroperitoneal laparoscopic operation; Partial nephrectomy; Segmental renal artery; Sequential clamping

Protective Effects of the Segmental Renal Artery Clamping Technique on Ischemia-Reperfusion Injury in db/db Diabetic Mice.

Renal ischemia-reperfusion (I/R) injury is inevitable in partial nephrectomy and other kidney surgeries, with a higher incidence in patients with renal insufficiency. This study aimed to investigate the protective effects of precise segmental renal artery clamping (SRAC) against renal I/R injury in db/db diabetic mice, compared with conventional renal artery clamping (RAC). Grape seed extract, a powerful free radical scavenger, was administered to diabetic mice for 4 weeks before operation in subgroups (30 mg/kg/d). The unilateral renal pedicle was ligatured, and I/R injury to the contralateral kidney was induced (ischemia for 30 min followed by reperfusion for 24 h). Blood glucose value, creatinine, blood urea nitrogen, and urine microalbumin/urine creatinine ratio increased gradually and showed no preoperative statistical differences among six subgroups. These parameters were significantly lower in the SRAC than in the RAC group 24 h postoperatively. Moreover, the nonischemic area in the SRAC group expressed less KIM-1 and TNF-α mRNA and also revealed minor histopathological damage induced by I/R. These findings suggest that SRAC effectively reduces early renal injury induced by I/R and accelerates the recovery of renal function in diabetic mice. Thus, SRAC may be an ideal technique in partial nephrectomy, especially for patients with diabetic nephropathy and other renal insufficiencies.

A retrospective analysis of laparoscopic partial nephrectomy with segmental renal artery clamping and factors that predict postoperative renal function

To evaluate the feasibility and efficiency of laparoscopic partial nephrectomy (LPN) with segmental renal artery clamping, and to analyse the factors affecting postoperative renal function. We conducted a retrospective analysis of 466 consecutive patients undergoing LPN using main renal artery clamping (group A, n = 152) or segmental artery clamping (group B, n = 314) between September 2007 and July 2015 in our department. Blood loss, operating time, warm ischaemia time (WIT) and renal function were compared between groups. Univariable and multivariable linear regression analyses were applied to assess the correlations of selected variables with postoperative glomerular filtration rate (GFR) reduction. Volumetric data and estimated GFR of a subset of 60 patients in group B were compared with GFR to evaluate the correlation between these functional variables and preserved renal function after LPN. The novel technique slightly increased operating time, WIT and intra-operative blood loss (P < 0.001), while it provided better postoperative renal function (P < 0.001) compared with the conventional technique. The blocking method and tumour characteristics were independent factors affecting GFR reduction, while WIT was not an independent factor. Correlation analysis showed that estimated GFR presented better correlation with GFR compared with kidney volume (R(2) = 0.794 cf. R(2) = 0.199) in predicting renal function after LPN. LPN with segmental artery clamping minimizes warm ischaemia injury and provides better early postoperative renal function compared with clamping the main renal artery. Kidney volume has a significantly inferior role compared with eGFR in predicting preserved renal function.

Effect of selective segmental renal artery clamping on the liver

Objective To evaluate the effect of selective segmental renal artery clamping (SSRAC) on the liver so as to provide a foundation for the using of SSRAC in partial nephrectomy (PN). Methods A total of 18 domestic pigs were randomized equally into 2 groups according to the method of renal artery clamping such as main renal artery clamping (MRAC) and SSRAC. Each subject underwent radical nephrectomy to right kidney, and then either MRAC or SSRAC was performed to left kidney for 60 minutes. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were measured before surgery and at 6 time points thereafter (day 1, 7, 14, 21, 28, 90). Liver histology was observed on the first day and the 90th day after operation. Results On the first day after operation, ALT and AST values of the MRAC group were (79.00±9.30) U/L and (264.00±59.85) U/L, which was significantly higher than those of SSRAC group [(52.80±5.81) U/L and (143.20±29.22) U/L, P 0.05). In the MRAC group the liver experienced extensive hydropic degeneration, partial hepatic cells vacuolization and multifocal necrosis on the 1st day, and the above pathological changes were significantly attenuated on the 90th day. However, the liver pathological injury in SSRAC group was less at the two time points. Conclusion Compared with MRAC, SSRAC has a protective effect on liver postoperatively. It's better to choose SSRAC during PN. Key words: Selective renal artery clamping; Main renal artery clamping; Partial nephrectomy; Ischemia-reperfusion injury; Liver injury

A model for assuring clamping success during laparoscopic partial nephrectomy with segmental renal artery clamping.

A model for assuring clamping success was established for laparoscopic partial nephrectomy (LPN) with segmental renal artery clamping (SRAC). Patients (n=107; December 2009-September 2011) who underwent LPN with SRAC dependent on the experience of the surgeon and CTA were retrospectively reviewed to determine the optimal characteristics of target arteries. After multiple logistic regression analysis, variables used to build a nomogram were selected using a backward elimination scheme. A model for a clamping program customized to the patient was designed. The surgical outcomes of patients (n=141; October 2011-June 2014) who subsequently underwent LPN-SRAC with the applied model were compared with those of the first group of patients. Five potential predictors were initially assessed: segmental renal artery angle, target artery diameter, and distance (d) to the abdominal aorta, renal hilum (d RH), and kidney midline (d KML). The regression equation was set up as: [Formula: see text]Comparing the patient groups, those for whom the new SRAC model was applied had a significantly better success rate of clamping (P<0.001), less total operative time (P<0.001), and less operative blood loss (P=0.042). No obvious differences were observed in time of warm ischemia, postoperative hospitalization, RENAL nephrometry score, or number of final clamped branches. The model for assuring clamping success was helpful in designing an SRAC program and thus benefiting the LPN procedure.

The study of selective segmental renal artery clamping aggravating pathological injury of the solitary-kidney in a porcine model

Objective To evaluate the effect of selective segmental renal artery clamping (SSRAC) on the solitary-kidney, providing a foundamental basis for the using of SSRAC in partial nephrectomy. Methods A total of 18 pigs were randomized equally into 2 groups according to the method of renal artery clamping such as main renal artery clamping (MRAC) group or SSRAC group. Each case underwent right radical nephrectomy and either MRAC or SSRAC for 60 minutes on the left kidney. Serum creatinine (SCr) and blood urea nitrogen (BUN) were measured before surgery and at 6 time points thereafter (the 1st, 7th, 14th, 21st, 28th, 90th day). Magnetic resonance imaging was performed before surgery and at 4 time points thereafter (the 1st, 7th, 28th, 90th day) and T2 relaxation time and apparent diffusion coefficient (ADC) were determined. Inflammatory cell infiltration and interstitial fibrosis were detected using renal histology on the 1st and 90th day after operation. Results SCr and BUN of the two groups increased to peak value on the 1st day, and then decreased gradually to normal on the 90th day after the operation. On the 1st day, SCr [(266.43±31.12)umol/l] and BUN [(13.63±2.54)mmol/l)] of SSRAC group were significantly lower than that of MRAC [(386.37±40.40)umol/l, (26.83±5.96)mmol/l] (P 0.05) on the 7th, 14th, 21st, 28th, 90th day. In the MRAC group, the T2 relaxation time of upper, middle and lower pole of the left kidney increased and the ADC decreased on the 1st day after operation. It arrived to the peak value on the 7th day, and decreased or increased respectively from then on to normal level on the 90th day. In the SSRAC group, there were no significant changes of T2 relaxation time and ADC in the upper and middle pole of left kidney (P>0.05), but it was similar to that in the MRAC group for lower pole. On the 1st, 7th, 28th day after operation, the T2 relaxation time of upper and middle pole of the left kidney in the MRAC group [(45.50±1.87), (51.82±2.27), and(40.37±1.93)ms ) ] were significantly higher than those in the SSRAC group [(36.67±1.33), (35.15±1.27), and(37.48±1.37)ms](P 0.05). On the 1st, 7th, 28th day after operation, the ADC of upper and middle pole of the left kidney in the MRAC group [(2.29±0.08)×10-3mm2/s, (2.10±0.08) ×10-3mm2/s, (2.41±0.09)×10-3mm2/s] were significantly lower than that of the SSRAC group [(2.69±0.08)×10-3mm2/s, (2.63±0.06)×10-3mm2/s, (2.68±0.05)×10-3mm2/s](P<0.05). However, on the 1st, 7th, 28th, 90th day after operation, the ADC of lower pole of the left kidney in the SSRAC group [(1.93±0.08)×10-3mm2/s, (1.91±0.09)×10-3mm2/s, (2.33±0.07)×10-3mm2/s, and (2.43±0.07)×10-3mm2/s] were significantly lower than those of the MRAC group [(2.37±0.05)×10-3mm2/s, (2.06±0.07)×10-3mm2/s, (2.46±0.09)×10-3mm2/s, (2.61±0.08)×10-3mm2/s](P<0.05). The whole left kidney in MRAC group experienced extensive tubular hydropic degeneration and limited inflammatory cell infiltration on the 1st day after operation. Moreover, renal tubular hydropic degeneration alleviated and no glomerular changes, fibrous tissue hyperplasia or inflammatory cell infiltration was found on the 90th day after operation. In SSRAC group, no changes were found in upper and middle pole of left kidney at the two time points, while the pathological injury of the lower pole of left kidney was more severe. Conclusions SSRAC has obvious protective effect on renal function in the early stage. However, compared with MRAC, the renal tissue injury in the ischemic area was more serious. Therefore, to protect renal function in partial nephrectomy, the ischemic renal area should be reduced as much as possible, even to zero-ischemic, when adopting SSRAC. Key words: Selective segmental renal artery clamping; Ischemia-reperfusion injury; T2 relaxation time; Apparent diffusion coefficient; Renal function